Si Stock airbox modified for cold air.

peters239

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@peters239 what are those four holes drilled in the box for?
That was done for a just incase i would go through some sort of deep water to keep from hydrolocking. Same idea as the 27won CAI. It does suck some air from the engine bay but not much and thats at idle. When you floor it they cant support all the air the turbo needs so it sucks most of the air from the 3 inch pipe. I d rather it get alittle hot air mixed in then worry about hydrolocking my only car.
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10GenPearlSi

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That was done for a just incase i would go through some sort of deep water to keep from hydrolocking. Same idea as the 27won CAI. It does suck some air from the engine bay but not much and thats at idle. When you floor it they cant support all the air the turbo needs so it sucks most of the air from the 3 inch pipe. I d rather it get alittle hot air mixed in then worry about hydrolocking my only car.
I left the stock intake open for the same reason. I figure that the new tube is so large that it doesn't suck much air from the stock intake opening until you get near WOT. Then I figure that extra warm air is better than starving the engine for air. I think it improves my power over 5000 rpm, but that is only by seat of the pants dyno.
 

peters239

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I left the stock intake open for the same reason. I figure that the new tube is so large that it doesn't suck much air from the stock intake opening until you get near WOT. Then I figure that extra warm air is better than starving the engine for air. I think it improves my power over 5000 rpm, but that is only by seat of the pants dyno.
Maybe once i get a drop in high flow filter it might feel alittle different but i doubt the 3hp they claim anyone can actually feel. What i do notice though is i dont think it pulls power after doing some spirted driving. I think thats the biggest benefit not getting heat soaked as easy.
 

10GenPearlSi

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Maybe once i get a drop in high flow filter it might feel alittle different but i doubt the 3hp they claim anyone can actually feel. What i do notice though is i dont think it pulls power after doing some spirted driving. I think thats the biggest benefit not getting heat soaked as easy.
Honda Civic 10th gen Stock airbox modified for cold air. 35144081_2073064769388196_5289999115541807104_o


What I was talking about is the Dyno chart above with the difference of the Stage 1 intake and the Cobra intake. If you look at the Stage 1 graph it shows the intake falling behind the Cobra above 5000 rpm. I think the reason that the Stage 1 falls behind is that it can't draw in as much air as the Cobra. Adding the duct, as we do, should allow more air to get in the airbox easier at high rpms and not fall so far behind the Cobra.
 

peters239

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I really need to get a drop in filter. Whats better a k&n or prls? I ve always use k&n's but prl says theres is better. Is it really that much better?
 


ApexEight

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Myx

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bling
still need to do the intake box and tubing

IMG_4059.jpg

This thread is GOLD (Pun Intended). Especially you folks that reported your before and after results from heat wrapping the intake. It's all I can think about now. ***I'm half toasted from doing shots...so don't mind me..*** I'm hoping to implement some heat wrapping this weekend. I had one additional thing I'm thinking about. If I can pull it off, I'll post up. It'll be like a 2nd barrier to prevent radiator heat/air from coming into contact with the turbo inlet piping and maf sensor.

Doing some 1/4 mile runs tonight, I noticed the turbo inlet pipe and maf sensor were really hot with the only thing causing it to be hot is the radiator fans blowing hot air on them (And perhaps some radiant heat from the downpipe. (The turbo has a blanket). I haven't setup my Ktuner Tunerview yet to look at IAT's just yet so will be winging it. Will post pics though of what I have in mind, in addition to the heat/gold wrap. Just wanted to thank you all again for this info. It's really helpful

Plus, I'm posting so I can look at this tomorrow and this weekend for reference. :p
 

Anger

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Didnt want to start a new thread as this has probably been discussed but cant find a specific topic:

I have been using the PRL SRI street MAF,either factory or Ktuner 21 DUAL and my STFT and LTFT have been spot on. Diviations around 0 were minimal and adding STFB + LTFT was always below 10.

Today,my LTFT is at -7 and my STFT is going from 0 to -17 momentarily, usually from -3 to -8.

I am kind of freaking out since I am not used to these kind of numbers, the street MAF has been working great so far. Any idea what might be wrong? This happens either on 21 PSI tune(canned,not custom) or ECO.

Any help is greatly appreciated...

EDIT: K Tuner stepped up once again. They replied within minutes for the question above. Turns out that the CRV maf calibration is pretty close to that of the Si, but not identical. So, despite not having issues so far, the ECU is starting to see that the maf readings are not what they should be. This issue as you all know, can be minimized by installing the stock airbox back or even better, by getting a custom tune. My tuner said he isnt too worried about these numbers and I definately dont want to lose the amazing PRL blowoff sound, but I guess I am back to stock airbox for the time being.

Any idea how far the trims must be off for the CEL to appear?!
 
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Myx

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Didnt want to start a new thread as this has probably been discussed but cant find a specific topic:

I have been using the PRL SRI street MAF,either factory or Ktuner 21 DUAL and my STFB and LTFB have been spot on. Diviations around 0 were minimal and adding STFB + LTFB was always below 10.

Today,my LTFB is at -7 and my STFB is going from 0 to -17 momentarily, usually from -3 to -8.

I am kind of freaking out since I am not used to these kind of numbers, the street MAF has been working great so far. Any idea what might be wrong? This happens either on 21 PSI tune(canned,not custom) or ECO.

Any help is greatly appreciated...

EDIT: K Tuner stepped up once again. They replied within minutes for the question above. Turns out that the CRV maf calibration is pretty close to that of the Si, but not identical. So, despite not having issues so far, the ECU is starting to see that the maf readings are not what they should be. This issue as you all know, can be minimized by installing the stock airbox back or even better, by getting a custom tune. My tuner said he isnt too worried about these numbers and I definately dont want to lose the amazing PRL blowoff sound, but I guess I am back to stock airbox for the time being.

Any idea how far the trims must be off for the CEL to appear?!

Sounds normal to me. Not your 'normal' normal but both your STFT and LTFT are both within normal ranges.
LTFT and STFT Operation

Short Term Fuel Trim (STFT) is what the engine computer is doing to the fuel mixture right now.

This value changes rapidly and can bounce around quite a bit depending on engine load, speed, temperature and other operating conditions).
Values normally range from negative 10 percent to positive 10 percent, though the readings may jump as much as 25 percent or more in either direction.
What Fuel Trim Values Should Be
Ideally, the STFT and LTFT should be within a few percentage points of zero when the engine is idling or being held at a steady RPM. Remember, STFT can bounce around quite a bit as when you suddenly snap open the throttle or decelerate. But LTFT can tell you if the average fuel/mixture is running rich or lean.

Good LTFT values should be as close to zero as possible, though they can range from 5 to 8 percent depending on the condition of the engine. If the LTFT is getting up around 10 percent or higher, it usually indicates a problem that needs to be diagnosed.

LTFT values that get up around 20 to 25 percent will usually set a P0171 or P0174 lean code.

LTFT values that drop down to negative 20 to 25 will usually set a P0172 or P0175 rich code.
 

Anger

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Sounds normal to me. Not your 'normal' normal but both your STFT and LTFT are both within normal ranges.
LTFT and STFT Operation
Thanks for the reply! Well, I remember having read here that a combined sum of 25 is not good. So when I saw that I am near that even momentarily, I kind of freaked out. To be honest at part throttle STFT is 0 to -8, jumping to -14 or -17 for a split second while LTFT is -7. These numbers may not cause a CEL but probably eventually will...

Have to say once again how awesome K tuner is. They reply to stupid questions like mine, really fast too!

Anywayz, tomorrow I ll reinstall the stock airbox(bummer) to see how things go. I also contacted PRL since they now have a CRV dedicated intake, so maybe that maf housing will work better....
 


CIVICUK

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Great read this guys! I am toying with adding an air duct to the bottom of my non si stock airbox using my prl cobra 4" hose, but i do have one suggestion. How hard/ what would it require to be able to cut out the stock maf housing and somehow bond the race maf from my prl cobra to the stock intake lid instead? I do have a buddy who said he could 3d print me the race maf so it would be of simular material to the stock air box, that way i could somehow get it to bond and run the prl race silicone hose also. The only thing obviously is i cant utilise the cone filter but i do have a foam panel filter currently installed.

Whats your thoughts on this guys?
 

CIVICUK

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Going back to the non si airbox, i was wondering if anyone has taken off the bottom resonator and made the hole (inside the attachment tube ) any bigger? I have attached some photos. Thinking i could add some piping to it for a small improvement of cold air ?

Thoughts please!
Honda Civic 10th gen Stock airbox modified for cold air. 20200808_164225
 

Sdgf92

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Going back to the non si airbox, i was wondering if anyone has taken off the bottom resonator and made the hole (inside the attachment tube ) any bigger? I have attached some photos. Thinking i could add some piping to it for a small improvement of cold air ?

Thoughts please!
20200808_164225.jpg
I've removed the resonator, haven't made the hole any bigger. I'm looking for a way to improve the cold air flow too!
 

Lushhater

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Anymore updates on your diy cai from stock box I got a 2020 si that I Wana do something similar. And can some tell me if these readings are good since I just tuned the car couple weeks ago.



Honda Civic 10th gen Stock airbox modified for cold air. Screenshot_20210927-090113_TunerView




Honda Civic 10th gen Stock airbox modified for cold air. Screenshot_20210926-152641_TunerView
 

KOIVUN1

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Anymore updates on your diy cai from stock box I got a 2020 si that I Wana do something similar. And can some tell me if these readings are good since I just tuned the car couple weeks ago.



Screenshot_20210927-090113_TunerView.jpg




Screenshot_20210926-152641_TunerView.jpg
just get a legit cai
if you're tuned you can get the street maf option to work with a stock-style tune, but if you haven't bought a dedicated tune yet you can get a race maf and buy a race maf tune.
diy cai isn't the way to go imo if you're already tuning the car. prl and 27won do a much better job than any amount of diy could ever do.
 


 


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